After the outbreak of the Fallen Bird virus, mankind fell into panic.
Level 1 carriers have super strong five senses, except for their red irises, which are the same as ordinary people.
Secondary carriers gradually lose their senses, live on human blood, and have a phoenix mark on their foreheads.
Level 3 carriers are diseased after their blood is sucked dry by level 2 carriers. They lose their senses and emotions and have to eat human flesh and blood to maintain their normal form. Their irises fade and cracks begin to appear on their skin.
These three inhuman beings led the government to create the Holy Angel House and the Human Self-Defense Forces, while the loopholes called seeds that people have been looking for and coveted have been hidden among normal people.